Bi-directional rings are used in data communications systems to provide high-speed data transmission with a number of safeguards to ensure fault tolerance. Optical networks using bi-directional rings are used in such data communications systems, but a great deal of overhead is associated with converting signals into the proper format required by most optical ring systems.
Other problems with prior art optical bi-directional networks are associated with the routing of data when a fault occurs in the system. When multiple channels of data are being sent over the optical. media, it is difficult and expensive to individually control the routing of the channels when a fault occurs. This is because in prior-art systems each channel must have its own fault detection and rerouting circuitry.
For these reasons, a need exists for an optical bi-directional ring communications system that simply and efficiently provides a means of detecting faults in the media, allows for the adding and dropping traffic to and from the media, controls routing of signals in the network, and provides a maintenance channel, wherein such a ring is also compatible with equipment currently in use.